1992 325ic - the lights glimmer or dim

[Mab1957]

1992 e30 - The lights glimmer or dim then brighten with increased rpm. Steady at idle. What should I test or looking for to return them to steady?

[jlevie]

At the least, a new brush/regulator assembly in the alternator and at the worst a new alternator. If the alternator bearing are good a brush/regulator may be all that's needed Also make sure that the engine to chassis ground is in good condition and making good contacts.

[Mab1957]

There was quite a squawking :( so it is likely time to replace the alternator. I will inspect the bracket, nut, belt and do the whole job.

Jlevie, thanks for the prompt assistance.

[Mab1957]

There's a Valeo in there now. Ever heard of a Valeo? Seems to spin OK, maybe one of the water pump, power steering pump or AC compressor are creating the squawking. Alternator belt, bracket and nuts look good too.

[jlevie]

If the bearings in the alternator don't make noise when you spin the alternator pulley or otherwise feel loose, the noise will be from something else. A likely candidate would be the water pump.

[drtwofish]

Not sure if this is what you're looking for, but I just replaced the voltage regulator in my Valeo alternator. My symptom was fluctuating lights (headlight and instrument lights) at idle that went away with revs. You sure the squawking isn't a worn belt? I'd hate to see you do a whole alternator replacement (Valeos are tricky to find) for just a voltage regulator.